Small animal imaging has become a very powerful tool for both drug development and in the understanding of diseases in animal models. The use of small animal imaging technologies has expedited the translation of basic science research to the clinic. Washington University School of Medicine (WUSM) is a world leader in the concept and design of new radiopharmaceuticals and drugs. Aiding in the screening of new radiopharmaceutieals are two state-of-the-art microPET tomographs. Conventionally, autoradiography has been used as a gold standard for determining the exact localization of tracer within small organ structures. This has become more difficult for new radiopharmaceuticals labeled with positron-emitting isotopes with short half lives such as C-11. An instrument with comparable resolution to autoradiography, but high sensitivity, will be extremely beneficial to augment microPET imaging, therefore streamlining the design and implementation of new radiopharmaceuticals. The Biospace a Imager offers the adequate resolution to answer these requirements. The system uses a new Parallel Plate Avalanche Detector that employs scintillation techniques and a CCD camera to more accurately locate the site of each decay event. In the a Imager, a gaseous mixture of argon and triethylamine vapor acts as the counting gas while crossed-wire grids operate at 3-4 kV, twice the usual proportional counting voltage. At each decay event, the electron avalanche produces gaseous scintillation; for argon, approximately 35 photons are produced per keV of beta particle energy with the output centered at 280 nm. The photons form a spot that is then viewed by the camera. Not only is that event recorded, but also the particle origin on the monitor in real-time. The Biospace Beta Imager offers a field of view/sample size of 200 mm x 250 mm suitable for whole mouse imaging and 4 levels of zoom. It has exceptional detection thresholds (e.g., 3H 0.007 cpm/mm2; 14C, 35S, 33p 0.01 cpm/mm2; 32p 0.1 cpm/mm2) and spatial resolution (Full-Width at Half Maximum as low as 60 fm for the smallest detectable feature) and a pixel resolution to 10 fm. The efficiency (the ratio of detected particles to number of particles emerging from sample) can be as high as 90% with a linearity of better than 2% over a dynamic range of 104. The instrument is supported by beta VISION +TM software for image analysis with the option for dual-isotope analysis. This proposal from WUSM, is to request funds for a Biospace a Imager to aid in the design and application of drugs and radiopharmaceuticals for the betterment of researchers from a broad range of disciplines, including ontology, neurology, chemistry and pulmonary medicine.